The paper is devoted to the acoustic analysis of a historical bell made in 1772. The paper presents basic measurements of the acoustic-vibrational characteristics of a small bell with subsequent analysis of selected parameters. Methods of analysis in the time, frequency and time-frequency domains were selected for the analysis. The conclusion presents an evaluation of the measurement method and evaluation. It also includes recommendations for further types of measurements and investigations.
This study investigates the transmission of structure-borne noise generated by water supply installations, with a particular focus on faucets. Laboratory experiments were conducted to evaluate the effects of various pipe fixing methods, wall elbow supports, and faucet types on noise levels. The measurements revealed that PPR clamps and rubber-lined clamps transmit varying degrees of noise depending on hydraulic shocks and water flow rates. Free-hanging pipes consistently demonstrated a significant noise reduction of up to 11.0 dB. The impact of wall elbow support and its attachment to the partition wall also proved critical, with complete removal reducing noise by up to 15.4 dB. The findings emphasize the role of minor construction details in noise transmission and suggest practical strategies to mitigate noise from plumbing systems, particularly in new residential buildings where irregular layouts exacerbate the issue. These results offer valuable insights for improving acoustic standards and minimizing noise complaints in modern housing developments.
This paper deals about the sound performance of loudspeakers and their influence by the design of the enclosures. Both enclosures were made of maple wood. Acoustic filling was also installed in both baffles, if it could improve the acoustic properties. Both speaker systems were subsequently tested in an anechoic room using the "sine sweep" method to compare their resonance characteristics and sound pressure level.
The work contains the analysis of selected bassoon fingerings, namely the first four bars of the Introitus part from W. A. Mozart's Requiem. The takes were recorded in the an-echoic room at the BUT Brno. The loudness curves, formants, spectral qualities using FFT are evaluated, and brightness, sharpness, spectral centroid are also measured. The duty cycles of the wave, including a pulse with a constant width, are taken into account, in connection with other double reed instruments. The analysis was performed both for entire phrases and for isolated tones. The fingering data are compared with each other (strengths and weaknesses) and evaluated from the point of view of aesthetics, i.e. how suitable the given fingering is for a different style and various interpretations.
This study focuses on the influence of the outer hair cells (OHCs) on the waves that propagate on the basilar membrane (BM). The human auditory system relies on the intricate organization of inner and outer hair cells within the cochlea. Inner hair cells serve as primary sensory cells, while the OHCs amplify signals. The activation of these hair cells is driven by the vibration of the BM and the overlying tectorial membrane. The spatial arrangement of hair cells along the cochlea enables frequency-specific responses, allowing the auditory system to process a wide range of sound frequencies. In this study, modal analysis is employed to explore the influence of the OHCs on the BM waves. The analysis model includes the BM and OHCs, with a comparison to a model excluding the OHCs. The frequency characteristics of propagation constants are compared between the two cases, shedding light on the structural dependence of propagation constants in the presence and absence of the OHCs.
